calm, cool and collected

(adjective) relaxed and confident

Example Sentence:

On my first day of school, I was so nervous about everything. My friend was calm, cool and collected!

She was calm, cool and collected before her presentation because she was well-prepared.

From the Blogs:

Mayor Daley is Calm, Cool and Collected

Media:

Similar idioms:

1. as cool as a cucumber
2. calm before the storm
3. beside oneself
4. hot under the collar